To discern whether Therion's OPTTM-series multi-locus DNA probes could address questions of relatedness and paternity in squirrel monkeys, 12 blood samples were submitted to Therion. The blood samples were from three unrelated adult males, two adult females and their three offspring sired by the three adult males. For comparison, a male-female pair and their two offspring were also analyzed. DNA was isolated from each sample and cleaved with restriction enzyme Hinf I. The DNA fragments were then separated electrophoretically (by size) and hybridized sequentially with the multi-locus DNA probes OPTTM-03A and OPT-05. The probes combination produces an informative and distinct set of DNA profiles. The average band sharing between unrelated males was estimated to be 45-52%. This compares favorably with observed values from other studies of unrelated primates kept in long-term captive populations, suggesting that this assay is an excellent candidate to address questions of parentage and relatedness in this species. All bands present in the profiles of offspring with known parents could be observed in the DNA profiles of one or both parents. These results further establish the utility of DNA profile testing for cases of parentage determinations. Paternity can be determined by identifying all bands in an offspring that are not shared by its mother ("informative" bands); all informative bands observed in the DNA profile(s) of an offspring must also be contained in the DNA profile(s) of its true sire. Only one of the three males exhibited the band pattern consistent with paternity and was determined to have sired each of the 3 offspring with unknown paternity. The utility of multi-locus DNA probes OPT-03A and OPT-05 for addressing questions of paternity and relatedness in squirrel monkeys has been established. *KEY*Genetics, Paternity